Sunstone Engineeering CD375DP dual pulse 375ws spot-welder

I bought this Sunstone Engineeering CD375DP dual pulse 375ws spot-welder on ebay for $600 a few months back, including foot-pedal, spot-welding leads, and wire-weldiong leads (on top). It came with the pictured pyramid power supply which recharges the caps really fast.

Nickel strip/sheet is expensive, so I farted around a long time before... jimw1960 posted on this thread http://www.endless-sphere.com/forums/viewtopic.php?f=8&t=28208&p=406657 a link to a123RC's website, where they were selling 0.2mm x 10mm (@ 0.008 x .40") nickel strip at a ridiculously cheap $2.59/meter. I took the plunge and bought 15m from this link:
http://a123rc.com/goods-268-1m+Pure+Nickel+Soldering+Tabs+For+Battery+26650.html

I didn't properly register the thickness; I was think .002", not .2mm. I was looking for .005", but I thought maybe I would layer 2-3 strips to .004" or .006", so I bought 3x more than I thought I might need. Now I have plenty of strip to play with.

This weekend I experimented on a 0v a123 M1 cell. .008 was a little bit thick for this welder. On the first go, it made welds that stuck, but not as strongly as I would like. I pulled off the tab and tried it on the other side, this time zapping each weld twice. These welds stuck, hard.



I wonder if I simply parallel the bank of the caps I assembled for my "<$100 resistance welder" project, I can increase the WS enough to punch through .008 with one zap. I have some molybednum rod I machined a ways pack for the same project, and maybe some 4gua leads, to upgrade the welding leads, that should help too.

I have a huge quantity of a123 1.1ah cells in 18v dewalt packs that I got from Doc, really cheap, a ways back. Next I need to try welding to the factory tabs that parallel each pair of these cells, I can fit 2 maybe three strips wide across those cells, enough to take a good amount of current. If it sorts out, I'll be making piles 'o discount cells for random applications... like one of the "Vector VEC012APC Start-It Elite Jump Starter and Power System" I bought in 2007, whose Lead-acid battery has died. I was going to replace the Pb, but I'll slap in as much a123 as I can fit, resolve the self-discharge woes and have be able to start, inflate, and light up entire fleets of vehicles between charges. :lol:

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EDIT: replace pictures that seem to have disappeared

oatnet said:

I wonder if I simply parallel the bank of the caps I assembled for my "<$100 resistance welder" project, I can increase the WS enough to punch through .008 with one zap.

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It would most likely blow the bejesus out of the switching transistors in the unit... I doubt that they designed in any kind of useful headroom.

texaspyro said:

oatnet said:

I wonder if I simply parallel the bank of the caps I assembled for my "<$100 resistance welder" project, I can increase the WS enough to punch through .008 with one zap.

Click to expand...

It would most likely blow the bejesus out of the switching transistors in the unit... I doubt that they designed in any kind of useful headroom.

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Thanks for the tip, TP!

Well, I'll work with it as it is then, double-zapping it is.

-JD

If you can get a piece of those stainless-steel can with that little guy, I would say you're doing pretty good! I bought a little welder off of ebay myself, It's pretty chintsy, but it does pretty well with traditional cells, Although I would never try an A123, because there's nowhere near enough juice. You got alot more for $600 than I did for $400 though, no doubt about it.

grindz145 said:

If you can get a piece of those stainless-steel can with that little guy, I would say you're doing pretty good! I bought a little welder off of ebay myself, It's pretty chintsy, but it does pretty well with traditional cells, Although I would never try an A123, because there's nowhere near enough juice. You got alot more for $600 than I did for $400 though, no doubt about it.

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Cool 8) which model welder, when did you get it? I seem to remember another Sunstone with less WS coming up right after mine... I was gonna bid, then realized I already had one on the way, a second would be stupid. :lol: Wonder if it was the same one.

-JD

I don't think double zapping will do much good either. It would be like putting too much energy into the first pulse of a dual pulse weld. The first pulse is only intended to blow away the crud in the joint. It should not cause the materials to stick. If it sticks, you have lowered the resistance in the joint to the point where the second pulse cannot produce enough heat to do a good weld. If you are zapping the same joint with two full pulses, the lowered resistance effect will be even greater.

I think that you may want to try preparing the tabs with small dimples (weldments) where you place the electrodes. This will concentrate the weld energy where the dimples are. Look closely at A123 tabs and you will see them.

Also split tabs are used to force the weld current through the tab and across the battery terminal to the other side of the split and not across a solid tab.

texaspyro said:

I don't think double zapping will do much good either. It would be like putting too much energy into the first pulse of a dual pulse weld. The first pulse is only intended to blow away the crud in the joint. It should not cause the materials to stick. If it sticks, you have lowered the resistance in the joint to the point where the second pulse cannot produce enough heat to do a good weld. If you are zapping the same joint with two full pulses, the lowered resistance effect will be even greater.

I think that you may want to try preparing the tabs with small dimples (weldments) where you place the electrodes. This will concentrate the weld energy where the dimples are. Look closely at A123 tabs and you will see them.

Also split tabs are used to force the weld current through the tab and across the battery terminal to the other side of the split and not across a solid tab.

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Thanks TP!

I got a spark on both of the dual-pulse welds (which I guess I should call quad-zapping not double-zapping :lol: ) so I thought I was getting a weld on each one. I did dial the first pulse down at some point, maybe that is what actually made the welds stronger, not the double zap. I'm glad that this little welder is up to the task, I just need to spend time getting to know it so I can produce consistent welds.

The pre-dimpling sounds like a good tip. Regrinding the trodes will probably get better placement, and going to 4ga wire should reduce resistance.

So to effectively use "split tabs", if I put two strips side by side, I could put one probe on each strip, to force the current through the material I am welding them to? Does proximity of the tips improve the weld?

-JD

Mines not from Sunstone, it's a "one hung-lo" special.... It's a self contained unit, that has the electrodes on a rocker arm on the side of the unit. As you push up on the electrodes, it eventually triggers the welder. I have to be honest, I took this thing apart and there are NO large capacitors in there. I have no idea how the thing works, but it does OK. But as far as I know, it's magic... Ill have to take some pictures and post them.

grindz145 said:

Mines not from Sunstone, it's a "one hung-lo" special... Ill have to take some pictures and post them.

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Please do post pics. Hmm, ebay, it seems I saw a 240v one from China listed a few times... Is that the one you got?

-JD

oatnet said:

So to effectively use "split tabs", if I put two strips side by side, I could put one probe on each strip, to force the current through the material I am welding them to? Does proximity of the tips improve the weld?

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Yes, that usually works very well. I would do the first welds with the probes on the outside of the strips, then move them in a step and do the next welds, etc. The idea is to try to minimize the shunting of current through existing welds.

Great tips, I'll use em, thanks!

Anyone here tried this $299 (+99 ship) battery tab welder yet? It looks like he as already sold (14) of them...

http://cgi.ebay.com/220678446838

-JD

oatnet said:

Anyone here tried this $299 (+99 ship) battery tab welder yet? It looks like he as already sold (14) of them...

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Spec'd at 10 KVA output. Theoretically, I can squeeze around 500 KVA pulses out of mine (with 1000J on the caps)... more like 250 KVA in the real world. At 10 KVA you should be able to weld AA cells with thin foil for use in radios... no way will it do meaty stuff.

oatnet said:

grindz145 said:

Mines not from Sunstone, it's a "one hung-lo" special... Ill have to take some pictures and post them.

Click to expand...

Please do post pics. Hmm, ebay, it seems I saw a 240v one from China listed a few times... Is that the one you got?

-JD

Click to expand...

This is exactly the one I have, I'm using a 1:2 Step-up transformer for it. Not the best welder in the world. I've used the professional $4000+ models at work, and you get what you pay for. You can make it work though. I've welded a few small packs with it. I doubt you'd make it through an A123 cell with one though.

So to effectively use "split tabs", if I put two strips side by side, I could put one probe on each strip, to force the current through the material I am welding them to? Does proximity of the tips improve the weld?

Click to expand...

Yep that helps. The negative tab is easy enough to weld on A123 M1, it is steel, the positive is a bit tricky, it is a nickel lamination on top of Auminium. Rubbing the tabs with some fine abrasive paper before welding doesn't hurt. 0.2mm might be a bit difficult for a fairly low powered welder, might need to go down to 0.15mm nickel.

I finally got around to giving this a good test. I have a 80 or so of the 18v Dewalt packs that have (12) of the 1ah a123 cells in them, ready to build into a pack. I harvested one, all the cells had held their voltage, so I spot-welded them together into a single 12ah cell.

The cells are already welded together in pairs inside the Dewalt pack, and the tabs joining the pair were super-easy to weld to, and afterwards I couldn't pull the tab off so I guess the welds were strong. I intended to just weld one pair to the same strip I used on the M1 cell above, but I got carried away.

It would be nice if I could pull 150a-200a from them, I'd build an exhibition pack for my CroMotor/Norco Aline project. The cells are so close together, and it looks like I could fit 3 nickel strips across the top, do you think with a bunch of welds on each cell, they could take 150a?


-JD